{Reference Type}: Journal Article
{Title}: Two types of cleavage, from zygote to three cells, result in different clinical outcomes and should be treated differently.
{Author}: Nemerovsky L;Ghetler Y;Wiser A;Levi M;
{Journal}: Front Cell Dev Biol
{Volume}: 12
{Issue}: 0
{Year}: 2024
{Factor}: 6.081
{DOI}: 10.3389/fcell.2024.1398684
{Abstract}: <B>UNASSIGNED: </B>What is the utilization rate of embryos that exert inadequate zygote cleavage into three daughter cells?<BR><B>UNASSIGNED: </B>This study used a retrospective dataset from a single IVF Unit. A total of 3,060 embryos from 1,811 fresh IVF cycles were analyzed. The cleavage pattern, morphokinetics, and outcome were recorded. Only 2pn embryos, fertilized by ejaculated sperm, and cultured in a time-lapse system for at least 5 days were included. We generated three study groups according to the embryo's cleavage pattern: (I) Control, normal cleavage (n = 551); (II) fast cleavage, zygote to three cells within 5 h (n = 1,587); and (III) instant direct tripolar cleavage (IDC) from zygote to three cells (n = 922).<BR><B>UNASSIGNED: </B>The rate of usable fast cleavage blastocysts was 108/1,587 (6.81%) and usable control blastocysts was 180/551 (32.67%). The time of PN fading and from fading to first cleavage differed significantly between the three groups. Although the pregnancy rate of control and fast cleavage blastocysts were comparable (40.35% and 42.55%, respectively), the amount of instant direct cleavage embryos that reached blastocyst stage was neglectable (only four embryos out of 922 analyzed IDC embryos) and unsuitable for statistical comparison of pregnancy rates.<BR><B>UNASSIGNED: </B>Our results indicate the need to culture instant direct cleavage embryos for 5 days, up to the blastocyst stage, and avoid transfer of embryos that are fated to arrest even when their morphological grade on day 3 is acceptable, whereas fast cleavage embryos could be transferred on day 3 when there is no alternative.